In case you did not know, the National Weather Service has specific criteria to determine whether a thunderstorm should be classified as "severe." Up until January 5 of this year, the criteria for a Severe Thunderstorm was as follows... A storm having either or multiple of these charicteristics:
Starting January 5, 2010, the hail criteria moved from a minimum of 3/4 inch to 1 inch in diamter. The other criteria has not changed.
Why the change you ask? After a year of doing research and polling various citizens and meteorologists across the country it was found that hail less then an inch in size does not cause enough damage to warrant much concern. For fear of the public starting to not take Severe Thunderstorm Warnings seriously, the National Weather Service thought it was in the best interest for all to bump up the hail criterium. In case you are wondering, 3/4 inch hail is considered "penny size hail" and 1 inch hail is considered "quarter size hail." Below is a picture to help show the different sizes of hail.

Do not worry, we will still inform you of any storms that are producing hail, however, we just might not call them "Severe!"